The present invention relates to a resin film comprising a vinylidene fluoride copolymer and an acrylic polymer as essential components. This resin film is excellent in blocking resistance, scratch resistance, transparency, water resistance and chemical resistance.
A resin film comprising a vinylidene fluoride copolymer (for example, a copolymer of vinylidene fluoride (VdF) and tetrafluoroethylene (TFE)) and an acrylic polymer (for example, polymethyl methacrylate) as essential components has been widely known, and also a transparent film made of such a resin film is known (for example, JP10-120801A).
Also coating with a coating composition comprising a vinylidene fluoride copolymer and an acrylic polymer as essential components for members for transportation cars (JP2001-49194A) and members for building (WO95/08582) is known well.
In the conventional coating and film comprising a vinylidene fluoride copolymer and an acrylic resin, a VdF-TFE copolymer having a VdF content of from about 70% by mole to about 90% by mole and a crystalline melting point of from 120° to 240° C. is used from the viewpoint of solubility in a solvent and compatibility with acryl, and a transparent film is obtained by blending the VdF-TFE copolymer to an acrylic resin containing not less than 50% by mole of methyl methacrylate. However this resin film comprising a vinylidene fluoride copolymer and an acrylic polymer as essential components is inferior in blocking resistance and has a problem that when the outside temperature is high, hardness of the film is lowered or when a load is applied on the film, craters remain.
When the melting point of the vinylidene fluoride copolymer is increased to solve this problem, a softening point of the resin film obtained from the copolymer and an acrylic polymer is increased but there is a problem that solubility in a solvent is lowered and further transparency of the resin film is also lowered.
Also there is known a method of crosslinking polymers in a resin film to improve blocking resistance. However in that case, there is a problem that adhesion at laminating the resin film on other material is lowered, and also extrusion moldability and welding resistance are lowered.